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    <title>Document</title>
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    <script>
        /* 
        Boolean【""空字符串\数字0 \undefine\null\NaN转布尔之后打印为false】**（重点）**
        */
       var a=123
       var b=Boolean(a);
       console.log(b);
       var s="";
       var b=Boolean(s);
       console.log(b);
       var s=0;
       var b=Boolean(s);
       console.log(b);
       var s=null;
       var b=Boolean(s);
       console.log(b);
       var s=undefined;
       var b=Boolean(s);
       console.log(b);
       var s=1-"hello";
       var b=Boolean(s);
       console.log(b);

    </script>
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